LESSON XXVIII. 



ORGANS OF TASTE AND SMELL. 



A. TASTE ORGANS. THE TONGUE. 



1. Longitudinal section of a papilla foliata of the 

 tongue of a rabbit (chromic acid *2 p.c. or potassium 

 bichromate 2 p.c.). Stain with hsematoxylin and eosin. 

 Observe 



The transverse section of the ridges with the 

 intervening fossae. 



In each ridge three papilliform processes of the 

 dermis, one median, two lateral. 



The horny epidermis, consisting of cells very 

 flattened but still showing nuclei, covering the ridges 

 and lining the fossae. 



The Malpighian layer of the epidermis. In the 

 fossae both layers of the epidermis are thinner and less 

 marked off from one another than on the surface. 



On the outside of each lateral papilla, and there- 

 fore lining each side of the fossa, the flask-shaped 

 taste-buds. There are usually four nearly in contact, 

 one above the other. Each bud is in contact by its 

 deeper part with the dermis of the papilla, and has a 



